a 5.5" x 1/4" Grade-5 Bolt.
But, like the Bench Press, you can't just train bench and expect to take off and set new PR's every day. Instead, you need to train the accessory muscles, the stabilizers, and the tendons used during the bend (bench) that support your main bending (benching) muscles and joints. Again, the best way to do this, is with a sledge hammer.
First off, I must clarify that I've bent a lot of nails before I bent a 5.5" x 1/4" grade-5. In fact, I have three large coffee cans (the two-pound cans) filled with bent nails. I bent some 25lbs of Timber Ties, and near 100 60D's, plus countless smaller pieces of steel. If I dumped out all the nails into one pile, it would speak for itself. The actul act of bending is by far the best teacher and developer of bending strength.
This is my absolute favorite wrist exercise and the technique that I feel has the most carry-over to bending. It doesn't mimic the bending motion, but it places extreme stress on the entire arm. When the sledge reaches parallel, it places A LOT of torque on the wrist and elbow. Here, you must squeeze the handle tightly, brace the wrist, and brace the elbow, and all three areas are being stressed quite thoroughly.
When doing this movement, keep the reps at or below 5. Doing more reps will not strain the tendons but will fatigue the muscles. Doing less reps leads to sloppy form and a loss of focus. For me, sets of 5 lets me keep focused and the weight is enough to stress all of my joints before I reach failure.
This is a fun one to do for an audience, but still teaches you the fundamentals of bending/levering: lock your joints tight so you can effectively use your strength. In this one, there's extra motivation, as if you fail you run the risk of flattening your nose or breaking some teeth. It's pretty simple, just flip the hammer over head, and lower it until parallel.
Traditionally, there is a lever done to the rear with a 1" rod of 4 feet in length, were you suspend weight from the far end and then lift it with just the hand. I don't have this set up, but work the sledge hammer in the same movement. I mainly focus on my left hand for this lift, as this muscle/tendon group is the primary bender in starting a bend with my left arm. I find that when I don't do this lift I end up irritating this muscle during bigger bends.
This is another way I play with the sledge. I like it because I don't use a set-rep scheme, and just toss it hand to hand until I'm smoked. Start by tossing the sledge from one hand to the other, keeping the hammer as parallel to the floor as possible. This is so when you catch it, your front-lever muscles must contract quickly and powerfuly against the hammer to deccelerate it, and then accelerate again so you can toss it back to the original hand. I also like this one because there are so many slight variations, such as the angle of how you catch it, the lenght of the handle you catch it at, the speed at which you toss it, ect. All stimulate a new area of your wrist. As you toss it, you mix it up until your entire lower arm is fatigued.
Nothing improves your short bar bending like bending more short bars. For me, the best plan and technique for training is the bend-when-ever-you-feel-like-it technique. I try to bend evey day and bend at least one 60D each day, and one 6"x1/4" grade 5 each week. Every bend teaches you technique and refines your skill. Every nail toughens your hands and tendons and makes you a better bender.
After turning our hands and wrists into a vise, and teaching our body to operate and bend as a whole, nail bending gets much easier. Bend to refine your technique and develop your bending power, and lever to build your base strength.
How to Bend a Nail: Photos
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